The genus Aquilaria is an angiosperm taxonomically placed in the Thymelaceaceae family. Fifteen species of Aquilaria have been reported and all produce agarwood. The taxonomy of these species is not completely clear and not all species are recognized by taxonomists. Species include Aquilaria malaccensis, A. agallocha, A. baillonii, A. crassna, A. hirta, A. rostrata, A. beccariana, A. cummingiana, A. filaria, A. khasiana, A. microcarpa, A. grandiflora, A. chinesis or A. sinensis, A. borneensis, and A. bancana. Aquilaria trees are native to Asia from northern India to Vietnam and Indonesia. They occur particularly in the rain forests of Indonesia, Thailand, Cambodia, Laos, Vietnam, Malaysia, northern India, the Philippines, Borneo and New Guinea. The Aquilaria tree is an evergreen that grows up to 30-40 meters high and 60 centimeters in diameter. It bears white flowers that are sweetly scented. The healthy wood of the Aquilaria tree is white, soft, even-grained, and not scented when freshly cut. Under certain pathological conditions, the heartwood becomes saturated with resin, and eventually becomes hard to very hard. The best grade of agarwood is hard, nearly black and sinks when placed in water. In general, agarwood lighter in tone is considered inferior as it has smaller amounts of resin.
The natural cucurbitacins constitute a group of diverse triterpenoid substances which are well-known for their bitterness and toxicity. They are characterized by the tetracyclic cucurbitane nucleus skeleton, namely, 19-(10→9 β)-abeo-10 α-lanost-5-ene (also known 9 β-methyl-19-nor lanosta-5-ene), with a variety of oxygenation functionalisies at different positions. Traditionally, the cucurbitacins are arbitrarily divided into twelve categories, incorporating cucurbitacins A-T. It is known in the art that cucurbitacins are cytotoxic and have anti-cancer activity. However, the application potential of cucurbitacins is substantially hindered by their non-specific cytotoxicity, and therefore, only very limited usage is pursued under strict medical control. Cucurbitacins were originally isolated as the bitter principles of the Cucurbitaceae, and were later found to be present, either non-glycosylated or glycosylated, in plants of the families Brassicaceae, Scrophulariaceae, Begoniaceae, Elaeocarpaceae, Datiscaceae, Desfontainiaceae, Polemoniaceae, Primulaceae, Rubiaceae, Sterculiaceae, Rosacease and Thymelacaeceae (Jian Chao Chen et al., Nat. Prod. Rep., 2005, 22, pp. 386-399). Sonja Sturm and Hermann Stuppner applies high-pressure liquid chromatography-mass spectrometry (HPLC-MS) to the analysis of cucurbitacins in medical plants and demonstrates its applicability through the determination of cucurbitacins in Citrullus colocynthis (Cucurbitaceae), Bryonia cretica ssp. dioica (Cucurbitaceae), Gratiola officinalis (Scrophulariaceae), Picrorhiza kurroa (Scrophulariaceae) and Iberis umbellate (Brassicaceae) (Phytochem. Anal. 11, 121-127 (2000)). HPLC methods are established for the simultaneous determination of four bioactive cucurbitacins in Cucubita pepo cv Dayangua (Cucurbitaceae) (Journal of Chinese Medicinal Materials, 2007, vol. 30, No. 4, pp. 418-420 and Chin Hosp Pharm J, 2007, December, Vol 27, No. 12, pp. 1694-1969).
However, none of the prior art provides information regarding cucurbitacins from Aquilaria agallocha or its hulls and the anti-cancer activity thereof.